Team SGK is probably one of the most controversial groups on the PS3 scene, which is at least part of the reason why a lot of their releases tend to get covered here. When it comes to the haters, they say that SGK makes copycat and unstable products that are useless when you consider the other options that you could have at your disposal. Regardless the group has worked to add some new features that could be worth highlighting of you want to see how deep the rabbit hole goes.
When it comes to features, this is a no spoof 4.31 build with the added developer benefits of QA Flag and all other major options found in previous releases. The rough Google translation of the changelog also makes mention of an “OS 31.4 compiler” and “all self SPRX” from version 4.31. As far as system compatibility is concerned no this does not work on any recent OFW releases. You can however boot it from any version CFW you like. Just be sure you have QA Flag enabled and System Update debug switched on before installation as long as those options are available to you. All the changes can be found at the source, but they are a confusing read.